Question: 4 crayons cost $4.56. Which equation would help determine the cost of 2 crayons?
Explanation: There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 4 crayons. We want to know the cost of 2 crayons. We can write the numbers of crayons as a proportion: $\dfrac{4}{2}$ We know 4 crayons costs $4.56. We can let $x$ represent the unknown cost of 2 crayons. The proportion of these costs can be expressed as: $\dfrac{\$4.56}{x}$ The cost changes along with the number of crayons purchased, and so the two proportions are equivalent. $\dfrac{4}{2} = \dfrac{\$4.56}{x}$